Propeller



Dec. 29, 1925- 1,567,528

W. R. M DONALD PROPELLER Filed July 27. 1923 2 Sheets-Sheet 1 Dec. 29, 1925- W. R. M DONALD PROPELLER Filed July 27. 1923 2 Sheets-Sheet 2 specification.

Patented Dec. 29, 1925.

UNITED STATES WILLIAM B. MCDONALD, OF SOUTH HOUSTON, TEXAS.

PBOPELLER.

Application filed July 27, 1923. Serial No. 654,113.

' To all whom it may concern:

Be it known that I, WILLIAM R. Mo- DONALD, a citizen of the United States, residing at South Houston, in the county of Harris and State of Texas, have invented certain new and useful Improvements in Propellers, of which the following is a This invention relates to new and useful improvements in an aeroplane propeller.

One object of the invention ,is to provide a propeller of the character described, having blades which are readily adjustable, so that their inclination, relative to'the plane of their rotation may be varied.

Another object of the invention is to provide a propeller having adjustable blades, and embodying amechanism whereby said blades may be readily adjusted by the aviator at will.

A further feature of the invention resides in the provision of a propeller having blades which may be dismantled separately, and

readily assembled together.

-With the above and other objects in view, this invention has particular relation to certain novel features of construction, operation, and arrangement of parts, an example of which is given in this specificationiand illustrated in the accompanying drawings, wherein v Figure 1 shows a fragmentary front end View of the propeller.

Figure 2 shows an enlarged fragmentary sectional view of'the blade anchor and the blade secured thereto.

Figure 3 shows a side view, partly in section, of'a modified form of propeller.

Figure 4 shows a transverse sectional View; and,

Figure 5 shows a fragmentary rear end view thereof. p

In the drawings the numeral 1 designates themotor having the forwardly projecting drive shaft 2. v

The outer end of the motor' shaft 2' is reduced and the propeller hub 33 is keyed thereon, said hub having the end spiders or plates 34 and 35, the former of which abuts against the annular shoulder 36, on said shaft, and against the latter of which the lock nut 37 threaded onto the outer end of said. shaft abuts. The cylindrical shell 38, formed of sections, conforms to, and fits around, said hub, said sections being secured at their outer ends by the hub cap A through said rack bars 39, which is threaded thereon, and at their other ends by the inwardly turned flanges 40 which engage over the corresponding end of the hub. A two blade propeller has been shown in this form, the blades being indicated by the numerals 41, 41. The bases of these blades are formed with circular flanges 42, which are formed with spur gears, and run in the raceways 43 of the shell.

In Figure 1 the shell surrounding the hub 1s formed of a plurality of sections as 10, preferably four in number. When fitted into position around the hub these sections form a. complete cylindrical shell and the end cap 11 is threaded onto the outer end of the shell to hold the sections in position. At their other ends these sections are clamped to the hub by means of the inwardly turned flanges 12 which engage over the inner end of the hub and they may be secured to the hub if desired by means of key-lugs 13, which are formed integral with the inner faces of the sections, and fit through suitable key-ways in the hub and interlock with the hub. The bases of the propeller blades 15 have circular flanges as 17 which run in raceways 18, in the periphery of the respective shell sections, and are provided with suitable anti-friction bearings as 19 as shown in Figure 2.

Splined on the shaft 2', between the hub and the motor, there is a disc 44, whose hub 45 has an annular groove 46, and there is a shift bar 47, operable by the aviator and whose inner end is forked and the prongs thereof have the studs 48, 48, which project into said groove 46.

There are two rack bars 49, 49, fastened at one end to the periphery of the disc 44, and whose other ends work in suitable bea rings provided for them, and are formed with rack faces which mesh with the respec tive gears 42. As the disc 44 is shifted through the shift lever 47, it will operate to vary the angle of inclination of the blades.

The rack bars are bolted to the disc 44, and consequently may be readily removed and the cap 39 then taken off and the propeller then easily dismembered.

This type of propeller will be useful for varying the speed of a plane without varying the speed of the motor, and particular y useful in slowing the speed preparatory to landing. v, p

What I claim is:

1. A ropeller including a hub having end spi ers, a cylindrical shell formed of sections to conform to and fit around the hub, said shell having circular raceways, a hub cap screwed onto one end of the shell and securin said sections together, inwardly turned anges at the "other ends of said sections which engage the corresponding end of the hub, propeller blades 10 having circular" fianges which run in said sections adapted to conform to and fit 5 around the hub, said shell having circular raceways, a hub cap screwed onto one end of the shell and securing said sections together, flanges at the other ends of said sections which eng e the corresponding end of the hub, rope ler blades having circular flanges which run in said .raceways and are formed with spur gears, a shiftable member and rack members connected to said member which work through bearings in one of said end plates and are in mesh with the blade flanges.

In testimony whereof I have signed my name to this specification.

WILLIAM R. MoDON 

